Abstract

We describe an extreme-ultraviolet (EUV)polarimeter that employs laser-generated high-order harmonics as the light source. The polarimeter is designed to characterize materials and thin films for use with EUV light. Laser high harmonics are highly directional with easily rotatable linear polarization, not typically available with other EUV sources. The harmonics have good wavelength coverage, potentially spanning the entire EUV from a few to a hundred nanometers. Our instrument is configured to measure reflectances from 14 to 30 nm and has spectral resolution . The reflection from a sample surface can be measured over a continuous range of incident angles . A secondary 14 cm gas cell attenuates the harmonics in a controlled way to keep signals within the linear dynamic range of the detector, comprised of a microchannel plate coupled to a phosphorous screen and charge coupled device camera. The harmonics are produced using , , and laser pulses with a repetition rate of 10 Hz. Per-shot energy monitoring of the laser discriminates against fluctuations. The polarimeter reflectance data agree well with data obtained at the Advanced Light Source Synchrotron (Beamline 6.3.2).

Received 24 March 2008Accepted 17 September 2008Published online 27 October 2008

Acknowledgments:

We acknowledge Elise Martin, Joseph Muhlestein, and Elizabeth Strein, as well as support staff at the Advanced Light Source for assistance with measurements. This work was supported by the National Science Foundation under Grant No. PHY-0457316.